Hydraulic cutting machine



L. D. BARLEY HYDRAULIC CUTTING MACHINE Original Filed Sept. 4, 1948 March 4, 1958 2 Sheets-Sheet 1 Zion 1:30 9% ow QTMW DZZOIgVEEITITOR BY ATTORNEYS March 4, 1958 L. D. BARLEY HYDRAULIC. CUTTING MACHINE Original Filed Sept. 4, 1948 2 Sheets-Sheet 2 V LgYII-INTOR United HYDRAULIC CUTTING MACHINE Leo D. Barley, Dayton, Ohio, assignor to Harris-Iutertype Corporation, a corporation of Delaware Original application September 4, 1948, Serial No. 47,833,

now Patent No. 2,649,153, dated August 18, 1953. Divided and this application February 13, 1953, Serial No. 336,725

7 Claims. (Cl. 164-54) This invention relates to cutting machines such as those used in the cutting of paper and the like, and is a division of parent application Serial No. 47,833, filed September 4, 1948, now Patent No. 2,649,153.

In the cutting of paper and other sheet material it is customary to provide a drive for actuating the knife, the knife being operated usually by mechanical means in a succession of cutting strokes following each of which the pile may be moved either manually, or automatically by automatic control of the movement of a back gage or spacer. It is also customary to provide a clamp for compressing the pile or stack of sheet material and holding it securely during the cutting operation of the knife. This is desirably accomplished by moving the clamp into holding engagement with the pile in advance of the engagement of the knife with the pile, the clamp being retained in holding relation during the entire cutting stroke and during at least a portion of the return stroke, until the knife has cleared the pile.

In accordance with the present invention the entire operation of the cutter is preferably hydraulic, both with respect to the operation of the clamp, and the knife. While the clamp requires only a limited amount of power, the power required by the knife is quite substantial during the actual cutting of the pile, and it is further necessary that the operation of the clamp and the knife be fully coordinated at all points in the operating cycle.

In providing for the proper actuation of the knife by hydraulic motor means comprising a piston and cylinder, it is necessary to utilize a relatively high pressure pump, as well as a working piston of substantial area, in order to develop the necessary force for operating the knife in the actual cutting of the material, such operation giving rise to a peak demand for power substantially in excess of that required over the remainder of the working cycle. Also, in order that the cycle may not be prolonged or delayed, it is important as a practical matter that the knife travel on its working stroke at a substantial rate of speed, thus requiring a pump capable of developing a considerable horsepower in supplying fluid at the necessary pressure and rate of flow. Further, it is undesirable that the knife slow up appreciably upon engaging the pile, and it is important therefore that the hydraulic system be capable of supplying fluid at a substantially uniform rate both prior and subsequent to the engagement of the knife with the pile, this also placing definite requirements on the source of supply of hydraulic pressure fluid.

The present invention provides for meeting these conditions and makes possible a full hydraulic cutter which has adequate power to perform the necessary work operation, to accomplish that work operation at a desired high rate of speed, and without material reduction in rate of travel when the knife engages the pile. Furthermore this is accomplished with the use of an economical source of driving power, much less than that required for the interval during which the peak load" 2,825,464 Patented Mar. 4, 1958 ice exists. The clamp is likewise hydraulically actuated, and is correlated in its action so that it engages the pile in advance of the knife, and remains in engagement therewith until after the knife has withdrawn from thepile. In addition, the system is adequately protected against damage to itself in the event of an excessive load being applied to the knife, the hydraulic pressure being relieved at a predetermined maximum safe point so that no damage will be produced even in the event of a positive stop being interposed under the knife, and it thus becomes unnecessary to utilize fracture links or similar releasable elements customarily provided in cutters hav in mechanically driven knives. The cutter is furthermore completely interlocked so that both hands of the operator are required to be in a definite safe location before the knife can be set in motion on its cutting stroke. It is also possible to control the clamp independently of the knife, providing for downward movement thereof at a predetermined rate, as Well as the stopping and return of the clamp from any position, under control of a treadle, in order to enable the operator properly to locate the pile in preparation for a subsequent cutting operation.

It is accordingly a principal object of the invention to provide a full hydraulic cutter in which the knife is operated rapidly and with a high degree of force throughout its entire stroke without requiring a source of driving power of correspondingly high horsepower output.

It is also an object of the invention to provide a drive source of relatively small output capacity for operating a hydraulic system for the actuation of the knife with the system providing for delivery of additional operating power to the hydraulic elements during the peak load conditions on the knife.

It is a further object to provide a hydraulic actuation cutter in which the operation of the knife and of the clamp are both accomplished by separate hydraulic mechanisms, the operation of which is fully coordinated throughout the entire cycle.

It is a still further object to provide a hydraulic cutter in which provision is made for relieving hydraulic pressure in response to an excessive load at such a point as to avoid damaging the mechanism.

Other objects and advantages will be apparent from the following description, the accompanying drawings, and the appended claims.

In the drawings- Fig. 1 is a perspective view of a typical form of cutter employing the present invention, certain parts being broken away to better show the construction.

Fig. 2 is a schematic view of the cutter of the present invention illustrating the drive mechanism and the hydraulic equipment for actuating the knife and the clamp; and

Fig. 3 is a diagrammatic view showing the control circuits for use in the system.

Referring to the drawings, an illustrative form of cutting mechanism is shown at 10 including a housing en closing the operating mechanism, a work receiving table 11, a cutting knife 12, and a clamp 13, located immediately rearwardly of the knife. A back gage is indicated at 15 and such back gage may also desirably be hydraulically actuated, such a construction being shown and described in copending application Serial No. 730,273, filed February 24, 1947, now Patent No. 2,649,155, and assigned to the same assignee as this application. An indicator 16 travels with the back gage which moves across a suitable scale 17 at the front of the cutter thereby indicating the position of the back gage and the corresponding length of material which will be cut. A foot treadle is shownat 20 which is utilized for controlling the opera- *-'-tion of the -clamp independently of the knife, and the I n sitiomof -the-safety --buttons=' -21--for--thelet-hand and 22 for the right-hand are'rshown at opposite sides of and t beneath theyvork; table 11 in position such that the hands -'-j--'of the"operator-when actuating both buttons; as required in' order fo1 the-machine to performa-cutting operation, {are red-loved :f-ronrth danger zone' th'e'range of opera-. ,'--'-tion'of the--knife. 7 Q 7 q Y I The--- knife "12' is-= indicatedsamewh tschematically in -1 =Fig.'-2; -'heingren1ovably carriedupon a knife barin-the usual WaW-ahd-the knifebanbeing guided'forreciprocat a'te'dsby :a hydraulie niotor indicated at 40 including a double acting piston :41 qmvable icylindei: 42' andiconnectedto bell;crank336 by means ofilinlcafirrf .Thus it will be evidentthat movementiof-the l 'ston :towarch the;';leftaa's.-.shown in .Fig."-2' will ;cause a 6;; ownwa'rdepull giponjtbothe-linksfifl and -3 l; causingithe knifezlzztcvsmove;downwardlyand with a component of 5:. itransvefserntovemnt;'onez endtraveling: downward at a .rfastercratel than: the other;:therebyxproviding. the l desired *xdoublmshearing action-in the course ofztheworkstroke.

Inwill: bemnderstoodzthatithezmeehanisrn isssuchsthat at abottomz qfizjthea stroke:;-thesknife..- assumes t alposition parallel with the cutting stick toitherebyproduce aiuni- 1:fomnxufiithrnnghoutithezentiredepthz'ofi the pile. I

'iSelective'i-cnntrol of: the operation ofithe knife "cylinder i=2 lsrobtainedby means of arfour-way knife valve indicated iindiagrammatically eitiSO; such valve convenientlyibeingof the type known as a four-wayopenicentertvalverjwhich is 3.:-Zsolenbid:reontrolledcand operated bypilotapressureii The ilot PIIESSIJIEQS}SHflPllfidi through .a'zpressure line. 521131111 iSTdlSCllflIgQd. backrttn the.;.tank; indicated diagrammaticallyl at 53, through dischargemutlet:54.;,.;Thefknifecnp Q1enoid,:,is :indicated rldi agrammaticallyr in fFig -3 at 55, lldilthfi Eknife;do,wn3:-.solenoid:at 56,:such' solenoids h'eing incorporated within the valve.-50.,:and-$erving.tovselective- 1y control the application of the pilotqpressure from line 52; which :is ithezpower actuallyiusedu to move the; main alveyihodyz; from onezpnsitionl'tos another.- eaway from a center. .s'f lermaimfluid pressnre;.-supply line is .shown at -58=. lea ing ,7 into;.-the.:iknife:.valve;50;sand connections 60 Dd? L. fixtcndrzbetwecm knifeglalvefaand the. cylinder for; supplying gflllidiifthfi ie tfi 1.: for :actuating itthe :knife; on

its down stroke and its up stroke, respectively; A counter-, balance va vi62 issincludediillrline'filiivhich allows free v flow of the fluid from valvel .-.5,0;toztheilowerqonleft hand i side elf-piston: 41: in :the directiomtomaise the: knife, but

ausingE;-the:iknife 'tc'tmoverkoneits Ldownward z. 011:;cutting strokeat aisubstantiallyauni-formratepcorresponding to hel-rate oflsupply Tofiiuid td the' pistomz: GWitha eonanlZffiOWibfilflllidffiflll'mlghfiuli thezst'roke; itlfollowssihat,

nsubsttintiallnmniform .ratesieveniaftenf engagement nvith vhichunaintains a back pressure; to hydraulically-counter: 1

iston-during-the; downward travel of; the knife; thereby the: pistomaizidflience'i:thes;zknifeiscontinuez:tcizgneve; at a r rate of travel= ou -its working-strokeofabout =7-inches per second and a slightly greater rate of return movement.

Fluid is supplied to line 58 through a proportional'filterf 5 65 and through a pressure relief valve 66 which is set to J relieve the pressure at apredetermined maximu nf the pressure when relieved being dischargedthroughvent' 7 67 to the tank." Thispressure relief va-lve -thus assures" againsttdarnage tow the s ystem hbeingset to carry gthe 10 'maximum lo'adzwhich theknife Willi,,encour fer;in a' cutting 1 operation, but relieving the system in response to an excess 7 r load so that even in the case of asolid obstructionain the the ,pressure"before' damage oceurs. ischa rge line.

68 returns the fluid from the'side of pistonf il not under 7 working pressure-from the,=valvej50 ;back to the tank and likewise provides for flow'of the entiretsupply of fluid to the tank without pressure when the'valve 50 is centered,

i; er, neither of its-solenoids being energized. This pro vides for unloading the pump which s uppli'es the fluid pres.

sure when'the knife ishot in'operation. H t 7 The main pump for supplying fiuid f Oractuating the knife 'is--indicated--at 70; being connected with supply tank 753." The pnmp170is ofrelatively large.- capacity;

' :and is eap ableof supplying the; fluid at the desiredghigh pressure-for instance ofthe orderfof "1,000 pound s per square inch; aHd"lik6WiS6 "ltj the desired high rat il 0f flo for exa ple of theiord r 33 llo migra 3) juteifj Such apun'ip, havingthisfluid output capacity, is '7 ir t f t approxi a ly or po e n would;

.mally; require a correspendingly highj 1outputjdrive or 4, mo or, .in or r td be capable-of developi git enecessary-powerjthroughout thejwhrkingfsitroke andama n- 5 taining v the full mateioi ,travel. 'ot the knife. during itsrjengagement with the lworksmaterial. T However in accordlance with,. tl .w presenttinyentionthe pump shaft 75 cargries, an inertia r'neans vin the' ior'm, of a flyr-wheelbflt i of p the knife engages and. passes" {through the work,n1aterial .on,its cutting stroke A fly-twheel having a'tvveight' of 5300 gpounds and an outer diameter of v 19 inches sand' rotated atofthe-t-order of, 1200 R. P. M.,-has-heen,used successfully. f fIhe ,fiy-vvheel is; suitably driven through Mt-belts 17-frorn an electiic-dr ivetmotor .t78,jthe;;motor' V t fl ein d fiv y;smallt ers n ueri ,sat.if a t9 y e t haic sbe n ew edtiw a u p. as. swe e scribed by; thevusej of a; motor "of ab out l Qhorsepower. .ilhej-systeni ;there f ore 7 avoids the expense :0 tall n s i n i s a:la -sc nar o: md rs u i r. 1 -.-1 m uts makes. i pessibt o, ac ate he puma. stout substantial; orngticeable reductiqn in spec -min m iau ht mallsm es t m er by he us 'o t an inertia: means, to. .Which energy; s supplied :peak periqdofithe -c'ycle and-from whichlenergyi is a a i w d ri r hs ak: l ad mfiodp h W s u eiot e zwheek s n in fl a ea isl-therefo 1. p t n. :thehyd au esyfiem o h GUl Q L-Z makes Po si e the deve opm nt of adequate. sp lw econgmicalg ns a,lla n-throu out- .z'Ihemclamnzlii 1 motor ,gwhich is ;;suppliedwith :hydraulicltfiuidi Undenpres- 65--;su;- frornga separate ;:pump, .the hydrauliczactuating.isystern for the clamp thus'being zseparate.i-ironntthatsfor -:tactuatingnhmknife.

:.ance with .diiierent:types ofrnateriahgetc; It is-hlso-sdes: 'sirzibleitu proyidewfor application ofzfull hydraulicgpresit hasaheemset lalgikewise it isiimportanb-toprovidejtfor the pile. With the system a s described," the knife has a lncthe' -.operationgof the iclamp it. rde mble tozhegableito; regulate the;;fo'rce:;with 5which t-:,the; .clamp:; engageszthe. zpile of work material 'insaccorda rapid rate of downward travel of the clamp toward the pile but without requiring such a large capacity pump as to increase the power requirements or to increase the losses. It is also necessary to correlate the action of the clamp with that of the knife so that in the complete operation of the system, the clamp will engage the pile in advance of the knife, remain in engagement with the pile until the knife has withdrawn above the pile on the return stroke, and then return to a release position to enable the pile to be handled or shifted either under manual control or under automatic control of the back gage as above referred to.

The clamp operating motor is indicated generally at comprising piston 81 movable in cylinder 82. The piston is connected by links 83 with a crank 84 secured to cross shaft 85 suitably journaled in the frame of the machine. Crank 86 and linkage 87 is provided at either end ofthe cross shaft and connected to the clamp 13 to provide for direct reciprocation thereof in a vertical plane in response to the rocking movement of shaft 85. It will be seen that the mechanism is such that travel of the piston 81 upwardly as shown in Fig. 2 results in downward clamping movement of the clamp 13. It will also be seen that the area below the piston is considerably greater than that above the piston, providing for developing a higher pressure to hold the clamp against the pile is then required to raise the clamp, the small area above the piston making it possible to raise the clamp rapidly.

The clamp valve is shown at 90, suitably being of the type known as a four-way closed center valve, solenoid controlled and operated by pilot pressure. Pilot pressure is supplied by pressure lines 92 and is discharged back to the tank through discharge outlet 94. The clamp up solenoid is indicated diagrammatically in Fig. 3 at 95, and the clamp down solenoid at 96. As in the case of the knife valve 50, the solenoids are incorporated in the valve and selectively control the application of the pilot pressure from line 92 which provides the power to move the main valve body. A discharge line 98 returns discharged fluid from the valve back to tank 53.

The separate supply pump for supplying the clamp operating pressure is shown at 100, having a filtered intake 101 within the tank 53 and connected to supply line 102. As shown pump is preferably mounted on the same shaft 75 as pump 70 and thus is driven by the same motor. The power requirements for operating the clamp being substantially less than for the knife, the pump 100 may provide for developing approximately the same high pressure, for example 1000 pounds per square inch, but has an output capacityof only about 7.5 gallons per minute, thus requiring about 5 horsepower.

In order to provide a source of pilot pressure for operating the several valves, an accumulator 105 is connected with each of pumps 70 and 100 through pressure lines 106 and 107 respectively, check valves 108 and 109 being included in the lines to allow one way flow only, in the direction to maintain a full pressure supply in the accumulator. It will be noted that both lines 52 and 92 are connected with the accumulator to thereby assure that full operating pressure will be available at all times for the actuation of these valves. A separate connection 110 may also be provided from supply line 102 for the actuation of the controls for the automatic back gage or spacer, in accordance with the system disclosed in said above referred to application Serial No. 730,273.

A clamp relief valve 112 is connected in the main pressure supply line 102 and a connecting line 113 leads to the clamp valve 90, the relief valve having a discharge line 114 leading back to the tank 53. This pressure relief valve is adapted to release in response to the development of the maximum pressure that it is dc 6 sired to have in the clamp system at any time, and fur thermorejto be capable of partial venting so as to prm duce any desired pressure between a minimum of substantially zero and the maximum.

In order, to be able selectively and remotely to control the pressure with which the clamp is applied a pressure line leads from the venting part of the relief valve 112 to a pressure pilot valve 121 which is also solenoid controlled. Solenoid 124 is shown diagrammaticaily in Fig. 3, and marked Variable Pressure, and solenoid 126 is similarly shown and marked Full Pressure, both such solenoids being incorporated in the valve 121. A discharge connection 127 leads from the valve 121 back to the tank, and is adapted to return pilot fluid released ,by the valve when set for minimum operating pressure, thus controlling the action of pressure relief valve 112 to discharge the main flow through line 114 and establishing minimum pressure in line 113. A connecting pressure line 130 leads from valve 121 to a manually adjustable valve 131, having a control handle 132 conveniently accessible to the operator, the pressure in line 130 being read on gage 133 located on the front of the machine, which is suitable marked to indicate the pressure for which the valve is set. Through the pilot action of valve 131, substantially the same pressure is established in line 113. A discharge line 134 leads from valve 131 back to the tank, the valve 131 thus functioning to relieve the pressure in the lines 130, 120, and 113 when it arrives at the value for which the valve had been set.

.Actuation of pressure pilot 121 therefore either closes oh the connection to relief valve 112, in which case full or maximum pressure is maintained in the system with excess fluid being discharged from relief line 114, or it opens the connection to valve 131, in which case the pressure in the entire clamp actuating fluid system is limited to that for which the manual control 132 is set. Thus either maximum pressure, or a predetermined variable pressure is selectively supplied to the line 113, and through it to the clamp actuating valve 90.

In response to the actuation of the clamp down solenoid 96, pressure fluid is supplied from line 113 through clamp valve 90 and pressure line 135 to the lower I side of piston 81, in the direction providing for downward movement of the piston. In order to provide for more rapid introduction of the fluid to the space below the piston, to thus enable a faster rate of fall of the clamp prior to the time it engages the pile, a supply line 136 leads directly from tank 53 to the lower side of the piston, a check valve 137 being included in this line to allow free inward flow of the fluid but preventing outward flow. Since the area of the piston is relatively large, it would normally require a large volume of flow from the pump in order to enable the clamp to fall sufii-- ciently rapidly without pulling away from the fluid, and this in turn would necessitate the use of a larger capacity pump 100. However through the provision of this direct supply line 136, the desired high rate of inflow of the fluid is made possible without increasing the capacity of the pump, and without requiring the development of any additional power. It will be understood of course that when the clamp engages the pi 2, there is no further free flow, and pressure is then supplied through line 135 to develop the desired clamping pressure, check valve 137 at this time closing and preventing escape of fluid from the cylinder.

In response to the actuation of the clamp up solenoid 95, pressure fluid is supplied through line 113 to valve 90, and from that through line 140 to the opposite or upper side of piston 81, in the direction to cause the raising of the clamp. A metering check valve 142 is included in line 140 of such character as to allow fiee flow of the fluid in the direction toward cylinder 80, while restricting the flow of fluid in the opposite direction to a predetermined rate. Thus fluid is supplied withoutrestriction to the upper-side of piston 81wltich trolling the fluid pressure in line 113 in accordance with the pressure for which manual control 132 has been adjusted. The clamp thereupon descends at the predetermined rate until it strikes the pile, and is then pressed against the pile with a force determined by the variable fluid pressure so established in the clamp system.

Actuation of the righthand button 22 also establishes a control circuit for initiating the operation of the knife, which may be traced from L through lefthand button 21, line 200, righthand button 22, line 205 and solenoid 206, through switch 207 to L Switch 207 is normally open and is not closed until the clamp crank arm 84 and arm 177 have moved an appreciable distance, thus assuring that the clamp will have already progressed on its downward stroke and be certain to precede the knife. Solenoid 206 is connected to the latch 208 which cooperates with a fixed abutment 210 on the knife connecting rod 38 to retain the knife in its raised or inoperative position, but until the weight of the knife is taken from the latch, the solenoid is ineffective and the knife remains in latched position.

A parallel circuit leads from line 205 through switch contacts 212 controlled by the latch 208, lines 213 and 214 to the knife up solenoid 55 embodied in knife valve 50. Upon actuation, valve 50 is thus energized in the direction to cause the introduction of pressure fluid from pump 70 through line 61 to the left of piston 41, and the knife is accordingly raised to its uppermost position against a stop formed by engagement of piston 41 with the head of cylinder 40, thereby relieving the load on latch 208, and enabling the solenoid 206 to release the latch.

As soon as latch 208 is released, the switch associated therewith opens its contacts 212 and closes its contacts 216, thereby deenergizing the knife up solenoid 55, and energizing the knife down" solenoid 56 through line 217 and closed switch contacts 218. Fluid pressure from pump 70 is thereupon supplied through line 58, valve 50 and line 60 to the righthand side of piston 41, the piston traveling downwardly at the rate permitted by the escape of fluid from the opposite side of the piston through valve 62 until the knife strikes the pile after which the stroke continues at the same rate, that is, the rate determined by the rate of supply of fluid to the piston in the manner just described.

The operator may wish to stop the downward travel of the knife at an intermediate point in the stroke, and this may be accomplished by releasing either or both the left and right hand buttons, such release opening the energizing circuit for the knife down solenoid 56, the knife valve then returning to its center or neutral position where it blocks the flow to both sides of the knife piston, and allowing the fluid to fiow freely back to the tank through vent 68, thereby providing for holding the knife in fixed position through a hydraulic block.

It may also be desirable to provide for maintaining clamp pressure upon the pile during this stoppage of the knife, and this may be accomplished after having released the right and left hand buttons, in the following manner. To accomplish this result a block 220 is frictionally mounted upon the knife connecting bar 38 and is movable over a relatively short travel between fixed stops 221 and 222, being frictionally carried by the connecting bar into engagement with one stop or the other, the bar continuing to travel through the stop after such engage ment occurs. The block has a cam face 223 on its lower side which is adapted to engage the operating end 224 of a switch arm 225 which is normally urged into circuit closing relation with the contacts 167 by means of spring 226. Thus after the knife has started its downward travel and block 220 has moved into engaging relation with the operating end 224 of switch 225, a parallel energizing circuit for the clamp down solenoid 96 and variable pressure solenoid 124 is established from L through line 228, switch contacts 229 and line 230, so that the clamp continues to be actuated against the pile notwithstanding release of either or both the left and right hand buttons.

When the knife reaches approximately the bottom of its stroke, or immediately prior thereto, an operating finger 235 carried by bell crank 36 is moved sufficiently far to cause the actuation of a snap action toggle switch 236 from the position shown where it has closed contacts 218 to its alternate position where it closes contacts 240. The opening of contacts 218 deenergizes the knife down solenoid 56, and for the extremely brief interval that the knife valve 50 requires to travel to its opposite position, the flow of hydraulic pressure is relieved. The bottoming of the knife piston 41 in the cylinder determines the maximum travel, and the knife connections 32 and 33 have previously been adjusted so that at this point the bottom edge of the knife has cut through the last sheet of paper and is in immediate contact with the cutting stick.

As soon as toggle switch 236 is tripped and switch contacts 246 closed, a circuit is established from L through normally closed switch 242, switch 240 and line 214 to the knife up solenoid 55, and fluid pressure is thereupon supplied through line 61 in the direction to cause the raising of the knife. As soon as the knife has bottomed at the end of its working stroke it is safe for the operator to release the buttons since the knife canno longer cause injury to his hands, and the circuit for the knife up solenoid as just described is therefore completed directly from L through toggle switch contacts 240, and not through'either the left or the right hand buttons. Retention of the righthand button will maintain the clamp in engagement with the pile, while release of the righthand button however restores the circuits to their normal conditions and results in return movement of the clamp.

It is desired however to keep the clamp in contact with the pile until the knife has cleared the pile on its up stroke and this is accomplished in the following way. Immediately upon the return or upward movement of the knife, bar 38 moves toward the right as shown in Fig. 3 and carries block 220 with it, away from stop 222 and into contact with stop 221, the bar continuing to move through block 220 after the latter engages the stop. Upon withdrawal of the block 220 from switch operating member 224, spring 226 restores the switch to the position where its contacts 167 are closed, but the circuit for the energizing of the clamp up solenoid and the full pressure solenoid 126 are not completed because knife 13 has not cleared the top of the pile and thus switch is open. Accordingly the clamp remains without change, i. e., in contact with the pile, until the knife on its return stroke has risen above the bottom of the pile, at which time its pad engages the operating member 172, closing switch 165, and thereupon energizing both the clamp up solenoid 95 and solenoid 126. Full pres: sure is thereupon at once applied to the clamp in the direction to cause it to rise, with the result that the clamp returns to its upper position where it is again latched and locked by latch 178 which has been released by solenoid 176 which occurred upon release of the lefthand button so that it stands in latching relation. Toggle switch 184 thereupon returns to the position where it opens switch contact 185, 'deenergizing relay 162 and thereby solenoid 126 in valve 121 whereupon the pressure in line 113 drops to the minimum. .Upon return of the knife to itsraised position, it'is also. locked in place by latch 208 which is released by solenoid 206 and drops back to latching position upon release of the righthand button.

The advantage of controlling the return movement of v the clamp in the manner described above will be understood in view of the fact that the heightof the pilewill vary over a considerable range, and with the control constructed and functioning in the manner herein set forth, assurance will be provided that the clamp will remain in contact with the pile throughout the down strokg a the -in required to clear the pile, but as soon as the knife'has Jeleai'ed the" pile;' whetherfthexpile i's high or low," -the damp-win promptly release and remrnfiof its raised po sition, thereby afiording a'maximum speed of operation 7 fo fthe entire machine consistent'withegood cutting;practice'.' -1 V t In orderto provide for "the actuation" Off-the clamp under control of=thefoottreadle20,1it is necessary-to actuate the leftha nd button :21,":whieh first"closes the fclamp 'np solenoid :95 andfullpressure solenoid 126 I to raise the"clamp,,,providing for'release'of latch "178 and the closing: of the 'energizing-circuit'for relay 162 in the 7 I 'imanner previouslyi described. Theqswitch 169 is' so{ ar p ranged that'it normally remains in closed position when thetreadlei's not operated, but immediately upon the depression-of the; treadle, a connecting pin 2 50 provides for opening switch contacts 169 providing for deenergie 7 zation'iof the .clamp up solenoid 95 .and full pressure solenoid 1-26. .Ihe clamp'direct-ional valve,90 returhs'l to neutralposition'inwhich closes all portsfand thes cape of fluid from above piston 81 i is regulated directly 7 -underfthe'controlof the'by-passvalve:152in accordance; V with the extent" of depression of treadle'zl); It will be 'seen that the-'clamp'c'a'nthusbe stopped in anyt desii'ed' zposit'ion merly -by' partially releasing the treadle 'but Without completely doing 80. V V

Fan depresses oftheitreadlresults in 'closingiswitch co'n tactsflfi "which theienp'o'n establishes the saint: circuit as' previously described forenergizing' the clamp :down

aperauenis' rancoordinate throughout -theentire-cycle =-ofoperation; an jm'ay' likwise-b'e iindpen'dentl '7 i V without any cerresp ndingtrave knife-' h shr'fikith which the elamp 15 appliedis readily d u able, and theclamp operation is controlle'd {in dtrect 1' relaiion fo thehight-"ofthe ileV fothat ftheclaihp-re;

mains in contactwith the pile,-wha ever its'hei'glit; ii I11 after the 'lgnife has Withdrawn above the top of the -pile;

The entire 'tne'chanism is thus highly economical;

protected with regard to the safety of boththe 'operator and the machine-itself,and is-completely flexible tto aci-fi t :contphsh whatever result 1 may be desired in the normal 7 operation o'f a cutter of thistype'. r

a {While the forrn of.- apparatus herein described co tutes a preferred "embodimentof the invention-fit be understood that the invention is 'not" limited :to

precise term of apparatus, and that changes may' he,

" made therein withont departing from the :scope'ofthe invention-whichis defined in theiappendedclainislj What is claimed isz p l1; iln'f a h'ydraulic cjntte'rhavin'g awbrk tahle to -re'ceive th'e -mzite'rial to 'be cut,- a knife mounted for reciprocationwith-'respect lto said table and-a clamp m0v+'- ia'bleitowardand away" from said tablej to clamp the work materialin position theron;"the icoinbinatidn' of separate v hydraulic motor means fe'ractuating said knife and *said "clamp respectively, a hydraulic pump J of relatively small: Z;

capacity for 'supplying fluid under pressure to said clain'p 7' solenoid 96iandvariablepressure 80161101115124, "thereby t 'establishing thepredetermined desired tpressureupon the "clamp' tohold it against the pile.. V or V V Full rel'easeof the tre'adle r'eclo ses switch'pontacts 169 1 and-restores the raising circuit 'for the'clanip whichthen returnsto' its fully raised position; Complete control" of "the clamp is' 'thusaobtained by manipulation of-the treadle; it

' It" is frequently? desirable to provide" forfthe? stopping of'theknifeat the bot'toni fofits stroke, as when it'is desired to 1 adjust theposi'tionof the bottom; edge of the knife,"and. in order toaccomplish this, the switch -242{is t provided in--the-supply line-leading to switch contacts 240 oflto'ggl'e swit'ch"236.; 'Switc h 242-i5-normally5 closed, 7 but when manually 'opene'd will provide forf stoppage of J fthe knife-at the bottomtof its stroke, preventing the'-'cIos-' ing ofthe circuitto the"-knife'up'- solenoid upon the. actuatiomof toggleswit'eh 236. The knife-,can- 'the'n 'he adjusted as 'desired;; following *which the restofing of 'switchf242 to the: closed position willTcompletethe'tup circuit-tonne knife andthe cycle will continue from thatpoint in the;-same manner as described above.

' 7 Where it is desirahleto inch the knife upward,- as when changing Y knivs,*-switch"2'42 may be released t eopen position-andthen manually closed inshort'repeated in 7 eams soas 'to-inch'orfiog thekn'ife upwardby small in 'c'renintsfi' Q 7 Itrna'y' alsoi be desirableat timesto provide? for imme;

diate" up ftrav'el of 'the knife from anyr actuate'd fdown-l stroke position andfin order' to provide for-"this opera 1 tifon'a switch" button 2fi5 is included in a parallel circnit '7 fdirectlyj' connected through line '214 to thetknif ej up actuating m otqr,:aiseparate liy'dranlit: pumpof relativelyf '7 large capacity for supplying-fluid under pressure to said}:

knife 'a'ctuating moton-taconimon continuouslyoperating j 'driv *mo'tor fo'r f drivingsaid {pumps' having away-Am '7 r 'tlforccintinuous actuation offsaidi'srnall'capacity I pump but' nsuflicie'nt for 'continnous, zaetuationjof said 1 rlarg'e capacity pump at the filll capacity 'fthereofymeans for operating sa dgclampfin "correlated relation twith ""d -kmfetoclamp the-work material on saidtable Iin *ad vanc'e o f th'e cuttingthereof by; said knife iutilizing' energy 7 supplied entirely by said drive motor,- and inertia means associated Withtsaid drive motor for supplyingadditional' V powerthereto durin'glthe cntting strol e of 'saidknife 'to niainta'in the speed of travel th eredfiby maintaining oper ation 0f said large capacity pump at'full capacityg i r 9 t 2. 111 a'- hydraulic; cutter having a 'wo'rktableadap id to receive thematerial to -be cut, knife mounted-for reciprocation resfpeet'to saidjltablej and a-clamp'niov-Y V ahlet'o'war d and way fr ohi said tableto-clanipfthelwork a material in p'osition thereom-the combination of hydralilic V 50 motor means'for actuating said knife' hydraulic 'rnotor naeansfforiactuating said amp-, a high'pfressure highcapacity hydraulic pump "for motor,- a' separatethighpress supplying fluid tosaid clamp diately energize-the knifewuptsolenoid; whichjreturnsfthe i i 5 knife to Eitsfraised' position. 'jIt is also preferablejitof in 4 corporate a contr ol' for ipreventing 'repeat "cycles unless the; control buttonshave been released inithe meantime ajs'uitable control for such purpose being shown in*Pat'-} fThe ystemjherei'n d'esgir'iheclfthns' provides a'ffnlly fa "tom-aha" hydrauhcputter with" adequatepoweri for' o'pi- 11- peak 'loa'd'ilnposed :uponjthe The knife onofrhothitheclamp andthefknifethroughout their? 7 tting'istrokesfbntwithout 'reqniringithe'highicapaeity t bl i iwhich wqulttotherwisebeneededtoi'develop -ahlef-fwardan a yftromsaidtahleftoiclantp the andaidanip, m g

Inateria intpositioirither'eon'theeornhination ofhy 'adapteg motor, a separate high pressure low capacity pump for supplying fluid to said clamp motor, a common drive operating continuously for actuating said pumps and hav mg a capacity sufiicient for continuous actuation of said low capacity pump but insuflicient for continuous actuation of said high capacity pump at the full capacity thereof, means for operating said clamp in correlated relation with said knife to clamp the work material on said table in advance of a cutting stroke of said knife utilizing energy supplied entirely by said drive, a fly-wheel forming part of said drive for supplying additional power to said knife actuating pump during the cutting stroke of said knife to maintain the speed of travel thereof by maintaining operation of said high capacity pump at full capacity, valve means for controlling the operation of said motors, an accumulator for storing fluid pressure for actuating said valve means, and means for supplying pressure fluid to said accumulator for both said pumps.

4. In a hydraulic cutter having a Work table adapted to receive the material to be cut, a knife mounted for reciprocation with respect to said table and a clamp movable toward and away from said table to clamp the work material in position thereon, the combination of hydraulic motor means for actuating said knife, hydraulic motor means for actuating said clamp, a high pressure high ca pacity hydraulic pump for supplying fluid to said knife Y motor, a separate high pressure low capacity pump for supplying fluid to said clamp motor, a common drive operating continuously for actuating said pumps and having a capacity suflicient for continuous actuation of said low capacity pump but insufficient for continuous actuation of said high capacity pump at the full capacity thereof, means for operating said clamp in correlated relation with said knife to clamp the work material on said table in advance of a cutting stroke of said knife utilizing energy supplied entirely by said drive, a fly-wheel forming part of said drive for supplying additional power to said knife actuating pump during the cutting stroke of said knife to maintain the speed of travel thereof by maintaining operation of said high capacity pump at full capacity, and a pressure relief valve connected in the line between said clamp actuating pump and said clamp motor for controlling the pressure developed by said clamp independently of said knife actuation.

5. In a hydraulic cutter having a work table adapted to receive the material to be cut, a knife mounted for reciprocation with respect to said table and a clamp movable toward and away from said table to clamp the work material in position thereon, the combination of hydraulic motor means for actuating said knife, hydraulic motor means for actuating said clamp, 'a high pressure high capacity hydraulic pump for supplying fluid to said knife motor, a separate high pressure low capacity pump for supplying fluid to said clamp motor, a common drive 'operating continuously for actuating said pumps and having a capacity sufiicient for continuous actuation of said W capacity pump but insuflicient for continuous actuation of said high capacity pump at the full capacity thereof, means for operating said clamp in correlated relation with said knife to clamp the work material on said table in advance of a cutting stroke of said knife utilizing energy supplied entirely by said drive, a fiy-wheel forming part of said drive for supplying additional power to said knife actuating pump during the cutting stroke of said knife to maintain the speed of travel thereof by maintaining operation of said high capacity pump at full capacity, a pressure relief valve connected in the line between said clamp actuating pump and said clamp motor for controlling the pressure developed by said clamp independently of said knife actuation, and a manually controlled pressure pilot valve for controlling the setting of said pressure relief valve.

6. In a hydraulic cutter having a work-table adapted to receive the material to be cut, a knife mounted for reciprocation with respect to said table and a clamp movable toward and away from said table to clamp the work material in position thereon, the combination of separate hydraulic motor means for actuating said knife and said clamp respectively, a hydraulic pump of relatively low capacity for supplying fluid under pressure to said clamp actuating motor, a separate hydraulic pump of relatively high capacity for supplying fluid under pressure to said knife actuating motor, a common continuously operating drive motor for both of said pumps having a capacity suflicient for continuous actuation of said low capacity pump but insuflicient for continuous actuation of said high capacity pump at the full capacity thereof, means including a pair of separate control valves for operating said clamp and said knife in correlated relation causing said clamp to clamp the work material on said table in advance of the cutting stroke of said knife utilizing energy supplied entirely by said motor, inertia means associated with said drive motor for supplying additionalpower thereto during the cutting stroke of said knife to maintain the speed of travel thereof by maintaining operation of said high capacity pump at full capacity, and means operable with said control valve for said knife motor for freely discharging said fluid pressure when said knife is not in operation to unload said knife-actuating pump between the strokes of said knife enabling the restoring of energy to said inertia means.

7. In a hydraulic cutter having a work-table adapted to receive the material to be cut, a knife mounted for reciprocation with respect to said table and a clamp movable toward and away from said table to clamp the work material in position thereon, the combination of separate hydraulic motor means for actuating said knife and said clamp respectively, a hydraulic pump of relatively low capacity for supplying fluid under pressure to said clamp actuating motor, a separate hydraulic pump of relatively high capacity for supplying fluid under pressure to said knife actuating motor, a common continuously operating drive motor for both of said pumps having a capacity sufflcient for continuous actuation of said low capacity pump but insufficient for continuous actuation of said high capacity pump at the full capacity thereof, means including a pair of separate control valves for operating said clamp and said knife in correlated relation causing said clamp to clamp the work material on said table in advance of the cutting stroke of said knife utilizing energy supplied entirely by said motor, inertia means associated with said drive motor for supplying additional power thereto during the cutting stroke of said knife to maintain the speed of travel thereof by maintaining operation of said high capacity pump at full capacity, said control valve for said knife having an open center position providing for free discharge of said fluid pressure when said knife is not in operation to enable the restoring of energy to said inertia means between the strokes of said knife.

References (Iited in the file of this patent UNITED STATES PATENTS 376,383 Higginson Jan. 10, 1888 1,200,802 Berry Oct. 10, 1916 1,398,822 Wilson Nov. 29, 1921 2,192,778 Stacy Mar. 5, 1940 2,208,966 Eickman July 23, 1940 2,341,494 Williamson Feb. 8, 1944 2,392,471 Fox Jan. 8, 1946 2,445,081 Pouille July 13, 1948 2,649,153 Barley Aug. 18, 1953 FOREIGN PATENTS 114,004 Great Britain Mar. 11, 1918 

